Post date: Jan 24, 2012 1:14:34 PM
In a series of experiments, the New Caledonian crow has demonstrated an unexpected understanding of how tools work to make their lives easier. The tests by scientists in the UK and New Zealand, revealed that the bird was intelligent enough to select and use the best available tool to raise the water level in a test tube. Jim Drury reports.
REUTERS / ALEX TAYLOR HANDOUT - Aesop's fable 'The Crow and the Pitcher' brought to life almost 3,000 years after it was written in ancient Greece.
The fable teaches that thoughtfulness is superior to brute strength, a lesson apparently not lost on the New Caledonian species.
Research from Auckland and Cambridge universities shows that New Caledonian crows demonstrate a cognitive awareness of how to use tools to feed. Dr Alex Taylor, who's done similar experiments with the rooks that reside on campus at Cambridge, says the crows are much smarter than previously thought.
DR. ALEX TAYLOR, POSTDOCTORAL RESEARCHER, DEPARTMENT OF EXPERIMENTAL PSYCHOLOGY, UNIVERSITY OF CAMBRIDGE, AND LEAD RESEARCHER ON CROW PAPER, SAYING:
"What our study shows is that they can learn to use stones as tools and more importantly they can understand something about how their tools actually work, so the crows were actually able to understand that a big stone is better to drop in than a small stone. It's a more efficient thing to do because it raises the water level more. They were able to discriminate immediately between floating and sinking objects. So they would pick up pieces of polystyrene and it would float and they would throw them away, and then they would pick up a rubber block that looked exactly the same but was nice and heavy and they dropped that into the tube."
Five crows were tested in their New Caledonia habitat and then released back into the wild.
The authors say the birds showed rational responses beyond simple associative learning.
DR. ALEX TAYLOR, POSTDOCTORAL RESEARCHER, DEPARTMENT OF EXPERIMENTAL PSYCHOLOGY, UNIVERSITY OF CAMBRIDGE, AND LEAD RESEARCHER ON CROW PAPER, SAYING:
"The kind of tweak in our study really was to try and explore, get some simple controls that would explore whether or not the crows were using simple learning, so that's something we hope to do at some point with these rooks as well."
Tool use has been observed in several species since the chimpanzee demonstrated that mankind is not alone in using implements.
But only a handful of bird species have previously shown this level of understanding. Taylor and his team believe their findings give them something to crow about.
Jim Drury, Reuters